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Breakthrough: Light recycling leads to huge efficiency gains

A technique called 'light recycling' has drastically improved the energy efficiency of incandescent light bulbs - here's how it works.

A team of MIT scientists has made a stunning discovery. According to a BBC report, researchers have described a new method for drastically improving the energy efficiency of incandescent light bulbs, called “light recycling.”

Incandescent light bulbs were once the most common type of bulb in the world, but have been phased out in many places because of their voracious energy demand.

The new method involves reclaiming the wasted heat energy from the incandescent bulbs and focusing it back on the filament inside. This allows the energy to be recycled in the form of visible light.

The study outlining the new method, which was published in the journal Nature Nanotechnology, offers the first drastic improvement to the efficiency of incandescent bulbs since they were invented in the late 19th century by none other than Thomas Edison.

Light bulbs have become a focus of the environmental movement, which has pushed for the adoption of compact fluorescent bulbs and more recently, LEDs to replace energy-greedy incandescent bulbs. It is difficult for these substitutes to match the warm glow of an incandescent bulb, however, and researchers have been searching for a way to deliver this light without wasting too much electricity.

The method involves a tiny structure surrounding the incandescent bulb’s filament, which captures any escaping infrared radiation. The structure reflects this energy back to the filament, which absorbs it and re-emits it as visible light.

The structure is made of carefully stacked crystals that can control the direction of infrared radiation, ensuring that it is directed back to the filament. According to Ognjen Illic, the lead author of the study, “It is not so much the material you make the surrounding structure from, it is how you arrange the material to create the optical filtering property that will recycle infrared light and let the visible light through.”

Researchers believe that the crystal structures surrounding the filament of incandescent light bulbs could increase their efficiency to nearly 40 percent, nearly three times that of the leading CFL and LED bulbs available. So far, prototypes have reached an efficiency of 6.6 percent. While this is roughly half of that of a standard CFL or LED, it is already three times the efficiency of a standard incandescent bulb.

While the researchers still have a way to go, the idea could revolutionize the light bulb industry forever.

An MIT press release outlining the light recycling method can be found here.